Speciation Analysis Of Organotin Compounds Research Articles

Speciation analysis of organotin compounds (OTCs) by a simultaneous hydride generation–liquid/liquid extraction and GC–MS determination

In the present work, the speciation analysis of three organotin compounds (OTCs), including tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT), by using simultaneous hydride generation–liquid/liquid extraction and GC–MS was developed. This simple method avoids the use of hazardous alkylation reagents without losing analytical performance. Multivariate design (central composite circumscribed, CCC) was applied for optimizing conditions on the hydride generation and liquid/liquid extraction. The optimized parameters were pH7.5 and NaBH4 concentration of 0.5% m/v. Hexane was the selected solvent for liquid extraction of OTC hydrides. Quantitative recoveries of OTCs were close to 100% in seawater samples, and the achieved detection limits for TBT, DBT, and MBT were 0.5, 0.4, and 0.7μgL−1, respectively. Obtained analytical figures of merit were comparable or slight lower than the most used method using sodium tetraethylborate (NaBEt4) derivatization and GC–MS. Nevertheless, the proposed method is characterized by its simplicity, low cost, and the used of highly available and safe reagents and could be considered as an alternative to the established procedure in those labs where NaBEt4 is not available due the restriction to its transport or safety requirements.

Speciation analysis of organotin compounds in human urine by headspace solid-phase micro-extraction and gas chromatography with pulsed flame photometric detection

A new headspace solid-phase micro-extraction (HS-SPME) method followed by gas chromatography with pulsed flame photometric detection (GC-PFPD) analysis has been developed for the simultaneous determination of 11 organotin compounds, including methyl-, butyl-, phenyl- and octyltin derivates, in human urine. The methodology has been validated by the analysis of urine samples fortified with all analytes at different concentration levels, and recovery rates above 87% and relative precisions between 2% and 7% were obtained. Additionally, an experimental-design approach has been used to model the storage stability of organotin compounds in human urine, demonstrating that organotins are highly degraded in this medium, although their stability is satisfactory during the first 4 days of storage at 4°C and pH=4. Finally, this methodology was applied to urine samples collected from harbor workers exposed to antifouling paints; methyl- and butyltins were detected, confirming human exposure in this type of work environment.

Toxicity and speciation analysis of organotin compounds

The use of antifouling paints in shipbuilding has led to a significant concentration of organotin compounds in the marine environment. Antifouling paints have become the main source of tributyltin and triphenyltin derivatives loaded into the sea. The toxicity of organotin compounds has been of great concern. High concentrations of organotin compounds are associated with growth abnormalities in mussels and oysters and have also resulted to the decline in their abundance. High concentration of organotin compounds have also been found in the tissues of marine mammals and its presence has been linked to mass mortalities of marine mammals. It causes imposex and calcification anomalities in mollusks. Seafood is thought to be a possible source of organotin compounds in human. Therefore, to evaluate the environmental distribution and fate of these compounds and to determine the effectives of legal provisions adopted by a number of countries, a variety of analytical methods have been developed for the speciation of organotin compounds in the environment. A detailed review of the toxicity and chemical speciation of organotin compounds is given.

Speciation Analysis of Organotin Compounds in Sediment by Hyphenated Technique of High Performance Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry

A hyphenated technique of high-performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) was applied to the simultaneous determination of five organotin compounds in the sediment samples. Agilent TC-C18 column was selected; mobile phase of the HPLC was CH3CN:H2O-CH3COOH(65:23:12, V/V), 0.05% TEA, pH 3.0 at flow rate 0.6 mL min−1, and 30% O2/Ar mixed gas was added to the make-up gas, which not only reduced the carbon buildup on the cones but also protected the cones. To reduce solvent loading on the plasma, the double-pass spray-chamber was peltier cooled to −5 °C. The high RF power (1500 W) helped the samples to decompose completely. A mixed standard solution of five mixed organotin compounds from 100 μg L−1 to 1 μg L−1 was used for the method assessment. The results indicate that the correlation coefficient of calibration curves (R2) for each organotin compound was over 0.998. The international standard reference PACS-2 samples were treated by supersonic extraction with mobile phase added 0.2% tropolone. Two organotin compounds including dibutyltin (DBT) and tributyltin (TBT) were detected with this method. The values of dibutyltin (DBT) and tributyltin (TBT) were 0.99 mg kg−1 and 0.83 mg kg−1, respectively. The results showed good accordance with the certified values. The recoveries from the standard addition for five organotins were over 80%.

Tartaric acid extraction of organotin compounds from sediment samples

A new extraction method for the determination of tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT) in sediments based on extraction with tartaric acid and methanol has been developed. Tin species were extracted from sediment samples using focused microwave technology, then ethylated with sodium tetraethylborate (NaBEt4) and analyzed by isotope dilution (ID) gas chromatography–mass spectrometry (GC-MS). The advantages of such methodology in comparison with other established extraction methods for the routine speciation analysis of organotin compounds are discussed with respect to sulfur interferences co-extracted from complex matrices.Interferences from elemental sulfur are normally found with acetic acid extraction, but with tartaric acid extraction these interferences were eliminated, demonstrating selective extraction.The accuracy of the analytical procedure was established by analyzing a certified reference material (CRM) (PACS-2, marine sediment) and comparing the results to the certified values. Good agreement between determined and certified values for butyltin compounds was obtained. Finally, some complex sediment samples collected from San Vicente's Bay, Chile, were analyzed with the proposed methodology, demonstrating its potential value for monitoring butyltins in environmental samples with high concentrations of sulfur compounds.

Speciation Analysis of Organotin Compounds in Shellfish by Hyphenated Technique of High Performance Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry

The hyphenated technique of high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) was applied to the simultaneous determination of five organotin compounds in the shellfish samples. The Agilent TC-C 18 column was used for the separation, the mobile phase of the HPLC was CH 3CN:H 2O:CH 3COOH = 65:23:12 (v/v/v), 0.05% TEA, pH 3.0, at a flow rate of 0.4 ml min −1. A mix standard solution of five mixed organotin compounds from 100 µg l −1 to 0.5 µg l −1 was used for the method assessment. The experimental results indicate that the correlation coefficient of calibration curves ( R 2) for each organotin compound was over 0.998. The shellfish samples were treated by supersonic extraction with the same mobile phase for 30 min. The four organotin compounds including dibutyltin (DBT), tributyltin (TBT), diphenyltin (DPHT), and triphenyltin (TPHT) in the shellfish samples were detected by this method. It was found that the domain compounds in the samples were TBT and TPHT. The recovery tests from the standard addition for TMT, TBT, and TPHT were over 80%. However, the recoveries of DPHT and DBT were relatively low, 37.3% and 75.2%, respectively. The reason might be attributed to the decomposition of those compounds during the extraction procedure.

Speciation of Organotin Compounds by Capillary Electrophoresis Coupled with Hydride Generation Atomic Fluorescence Spectrometry

Capillary electrophoresis (CE) coupled with hydride generation atomic fluorescence spectrometry (HG‐AFS) was developed for the speciation analysis of organotin compounds. The four organotin cations of trimethyltin (TMT), monobutyltin (MBT), dibutyltin (DBT), and tributyltin (TBT) were completely separated by CE in a 50 cm×75 µm i.d. fused‐silica capillary at 15 kV and using a mixture of 50 mmol l−1 H3BO3−50 mmol l−1 Tris‐5% v/v methanol (pH 7.10) as electrolyte. 0.008 mmol l−1 cetyltrimethylammonium bromide (CTAB) added to the electrolyte suppressed the adsorption of the organotin cations on the inner wall of capillary. The generated hydride species were detected on‐line with AFS. The precisions (RSD, n=5) were in the range of 1.7–3.1% for migration time and 3.8–4.7% for peak area response for the four organotin species. The detection limits ranged from 1–10 µmol l−1 (as Sn).

Detection techniques in speciation analysis of organotin compounds by liquid chromatography

Analysis of organotin (OT) species in the environment demands very selective, sensitive methods. Liquid chromatography (LC) with a suitable detection system is one of the techniques of choice. The constraints imposed by the required sensitivity mean that, among the instrumental techniques used for detection with LC, only inductively-coupled plasma-mass spectrometry (ICP-MS), mass spectrometry (MS) and fluorimetry are well suited to environmental OT analysis. This article reviews the applications and compares the performances of these detection systems coupled with LC for OT analysis.

Speciation analysis of organotin compounds in lard poisoning accident in Jiangxi Province, China

Speciation analysis of organotin compounds in lard poisoning accident in Jiangxi Province, China

Speciation analysis of organotin compounds in lard poisoning accident in Jiangxi Province, China

Samples including organotin contaminated lard, urine, blood, and main organs of the poisoned bodies were collected in the incident which took place in Longnan and Dingnan counties, Jiangxi Province, China around the new year’s day of 1999. The organotin compounds in these samples were identified and determined by gas chromatography-flame photometric detector (GC-FPD), gas chromatography-mass spectroscopy (GC-MS) and inductively coupled plasma- mass spectroscopy (ICP-MS). Experiments confirmed that tri- and dimethyltin are the main components that caused the poisoning accident. Monomethyltin, dioctyltin and inorganic tin were also found in several samples.

Simple and effective gas chromatographic mass spectrometric procedure for the speciation analysis of organotin compounds in specimens of marine mussels. An evaluation of the organotin pollution of the lagoon of venice.

This paper describes a simple, effective analytical procedure, based on a gas chromatographic mass spectrometric technique, for the speciation analysis of organotin compounds (OTC) in mussel samples. The direct alkylation reaction of the organotin chlorides in the aqueous digestion solution by NaBEt(4) allowed a short analysis time and a good recovery. The evaluation of the yield of each step constituting the analytical procedure indicated that the alkylation step is the most critical one. The proposed method was advantageously utilised to monitor the level of OTC pollution of the Lagoon of Venice. All the sites examined, both near to and far from anthropogenic activities, revealed significant levels of OTC pollution.

Investigating the potential of high-performance liquid chromatography with atmospheric pressure chemical ionization-mass spectrometry as an alternative method for the speciation analysis of organotin compounds

Liquid chromatography with atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS) was applied for the determination of butyl- and phenyltin compounds. Chromatography was performed on a 30 x 2 mm, 3 microm C18 column, enabling the separation of mono-, di- and trisubstituted butyl- and phenyltin compounds in less than 10 min using a water/1% trifluoroacetic acid/methanol gradient. While satisfactory retention and resolution is achieved for the di- and trisubstituted butyl- and phenyltin compounds, monobutyltin and monophenyltin cannot be resolved chromatographically. Depending on the parameter values of the interface, APCI-MS detection allows both specific detection of the molecular ion or cluster ion at low to intermediate fragmentor voltages or quasi-element specific detection of the Sn+ ion released from the organotin compounds at high fragmentor voltages. The sensitivity of MS detection is similar for butyl- and phenyltin compounds, but varies largely from mono- to trisubstituted organotin compounds with tributyl- and triphenyltin being the most sensitively detectable compounds. Detection limits are in the 20-65 pg (abs.) range in SIM mode and in the 750-2000 pg (abs.) range in the scan mode for tributyl- and triphenyltin and for dibutyl- and diphenyltin, respectively. Monobutyl- and monophenyltin can be detected with much lower sensitivity which, together with their unfavorable chromatographic behavior, accounts for the fact that they cannot be analyzed at environmentally relevant concentrations. Although LC-APCI-MS is generally less sensitive than comparable GC methods, it is applicable to the analysis of environmental samples as demonstrated by the analysis of the PACS-2 sediment certified reference material. Although the derivatization of the ionic organotin compounds, which particularly in real samples is a potential source of error, is circumvented when LC-APCI-MS is used, the extraction step is still critical and may lead to underestimation when quantitation is not done by the method of standard addition.

Speciation of organotin in sediments by multicapillary gas chromatography with atomic emission detection after microwave-assisted leaching and solvent extraction-derivatization

Microwave-assisted leaching of organotin compounds from sediment samples followed by the simultaneous extraction-derivatization of the extracted species was revisited with the goal to compare the existing procedures, improve their recoveries and extend them to phenyltin compounds. The stability of butyl- and phenyltin compounds under microwave field, real recoveries of the whole analytical procedure, effect of the extraction solvent, and the necessity for an internal standard were evaluated using two candidate reference sediments. The combination of the optimized sample preparation procedure with multicapillary chromatography resulted in a rapid (2 min leaching + 5 min extraction-derivatization + 3 min chromatographic separation) and efficient analytical procedure for speciation analysis of organotin compounds in sediment samples. The detection limit achieved with a microwave-induced plasma atomic emission detector was 2 ng g–1.

Elemental Speciation Analysis by Multicapillary Gas Chromatography with Microwave-Induced Plasma Atomic Spectrometric Detection

Multicapillary column gas chromatography (MC-GC)/microwave-induced plasma atomic emission spectrometry (MIP AES) was developed for fast speciation analysis of organotin compounds in the environment. Ethylated butyltin compounds could be separated isothermally within less than 30 s (instead of ∼5-10 min) without sacrificing either the resolution or the sample capacity of conventional capillary GC with oven temperature gradient programming. Careful optimization of the pressure and temperature GC program allowed a comprehensive organotin speciation analysis including phenyltin compounds within less than 2.5 min, increasing the sample throughput 6-fold. Compatibility of MC-GC with an MIP atomic emission detector (MIP-AED) was discussed. MC-GC/MIP-AES was validated for the analysis of sediment (PACS-1 and BCR 462) and biological (NIES11) certified reference materials.

Speciation analysis of organotin compounds in Thermaikos Gulf by GC-MIP-AED

A rapid, sensitive and interference-free analytical procedure was applied to organotin speciation in sea water. The method was based on the ethylation of ionic organotin compounds in the aqueous phase with NaBEt4, followed by extraction of the derivatized species into hexane. The separation and determination of organotin species were performed by capillary Gas Chromatography-Microwave Induced Plasma-Atomic Emission Detection (GC-MIP-AED). The operational variables were ortimized for chromatographic resolution and detection limits. 100 mL of sample were used for the analysis and the detection limits, for butyltin species, were ranging from 17.7 to 33.4 ng/L (as Sn) and for phenyltin species, from 17.8 to 22.3 ng/L (as Sn). The method was applied to the determination of organotin species in samples collected from Thermaikos Gulf (Thessaloniki, Greece) at 4 sampling points and 3 sampling campaigns. The sampling points represented industrial, urban and harbour activities. In three samples collected during the second sampling campaign, and from three sampling points respectively, only dibutyltin species were present at concentration levels close to the detection limits.

Interferences generated by organic and inorganic compounds during organotin speciation using hydride generation coupled with cryogenic trapping, gas chromatographic separation and detection by atomic absorption spectrometry

Hydride generation reactions are frequently used for the speciation analysis of organotin compounds in a wide variety of matrices. However, the organotin determination procedure may be altered by different interferences mechanisms. This work evaluates the interferences likely to occur in the determination of tributyltin in a harbour sediment candidate reference material for the EEC Community Bureau of Reference with the method of hydride generation combined on-line with cryogenic trapping, gas chromatographic separation and detection by atomic absorption spectrometry. First, a full geochemical characterization of the sediment and of its acetic acid leachate was achieved to evaluate interfering compounds that may inhibit the determination of TBT by hydride generation in this sediment. Second, interference studies on various organic and inorganic compounds likely to alter the overall organotin determination were carried out with simple model solutions. These model solutions were spiked successively with different possible interfering compounds mixed with the organotins under study, i.e., monomethyltin (MMT), monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT) in a mixed solution at concentrations of 5 ng as Sn of each compound in 50 ml of water. Organic interferents studied were organic pollutants (organic solvents, polychlorinated biphenyls, pesticides, n-alkanes), humic substances and a complexing agent, EDTA. The inorganic interferents were represented by a mixture of fourteen inorganic metals. The addition of organic compounds to the hydride generation reaction had little effect on the signal suppression for all organotin species. Reproducibility was significantly affected only by the presence of humic substances in solution. Signal suppression was observed only for the monoalkyltins (MMT and MBT) in the presence of EDTA. Solutions of mixed inorganic metals were found to be highly efficient in inducing severe signal suppression for all organotin compounds at a level of 100 μg of each element. Interference mechanisms during the speciation determination step are outlined and discussed.